Grinding machine



Dec. 7, 1937. c H AWD N 2,101,787

GRINDING MACHINE Filsd March 30, 1936 s- Sheets-Sheet 1 I I CHARLES HAM/DUN 1525 i Dec. 7, 1937;

c. H. AMIDON 2,101,787

GRINDING MACHINE Filed March so, 1936 5 Sheets-Sheet 2 A A I92 I 7 @670 \i /3/ w 450 3 mm l 0 CHARLES H. AM/DON FI 4 M Patented-Dec. 7, 1937 UNITED STATES GRINDING MACHINE Charles H. Amidon, Worcester, Mass assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application March 30, 1936, Serial No. 71,543

10 Claims.

This invention relates to grinding machines, and more particularly to a hydraulically driven tool and cutter grinding machine.

One object of this invention is to provide a hydraulically operated tool and cutter grinding machine with an interlocked driving mechanism between the. fluid pressure reciprocating mechanism and the manual traversing mechanism. Another object of this invention is to provide a fluid pressure reciprocating mechanism for the work support which permits one complete reciprocation of the table and then stops the table in a predetermined position at the end of its stroke. Other objects will be in part obvious or in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. l is a front elevation of the improved grinding machine;

Fig. 2 is a fragmentary right-hand end elevation of the machine as shown in Fig. 1, having partsbroken away and shown in section to more clearly show the operation and construction;

Fig. 3 is a cross sectional view, taken approximately on the line 3-3 of Fig. 1;

Fig. 4 is a diagrammatic view, showing the fluid pressure system together with the interlock between the fiuid pressure and the manual traverse mechanism;

Fig. 5 is a fragmentary front elevation, having parts broken away to more clearly show the table controlling mechanism;

Fig. 6 is a fragmentary sectional view, taken approximately on the line 65 of Fig. 1, showing the control valve and its operating mechanism;

Fig. 7 is a fragmentary vertical section, taken approximately on the line 'l--1 of-Fig. 2, showing the slide construction together with the elevating mechanism for the grinding wheel unit; and

Fig. 8 is a fragmentary sectional view, taken approximately on the line 88 of Fig. 1, showing the multiple speed device for manually traversing the table.

A grinding machine embodying this invention has been illustrated in the drawings, which comprises a base It] which supports a vertically extending column II. The column II is provided with a cylindrical bore I! which serves as a support for a cylindrlcally shaped post 13. The

upper end of the post I3 is provided with a grinding wheelsupport I4 which may be angularly' drives through belt to a pulley 2| formed on the end of the wheel spindle l5.

The post I3 is arranged to be adjusted verticall'y so that the position of the grinding wheel spindle l5 and grinding wheel It may be adjusted in a vertical plane relative to the base ID. This is preferably accomplished by means of a rotatable screw 24 which is rotatably supported in a bearing 25 in a portion of the base l0. The screw 24 passes through a nut 25 which is fixedly mounted in the lower end of the column l3. By rotating the screw 24, the nut 26 together with the column l3 and the grinding wheels l6 and I1 may be raised orlowered, as desired. In order to facilitate vertical adjustment of the wheel unit, a manually operable hand wheel 30. is mcginted on the outer end of ashaft 3i, the inner end of which carries a bevel gear 32 which mesheswith a bevel gear-33 keyed on the lower end of the feed screw 24. By rotating the hand wheel 30, the screw 24 may be rotated to vertically adjust the positions of the grinding wheels l6 and IT. A graduated collar 34 is associated with the hand wheel so that the extent of ad justment may be readily determined In the preferred construction, it may be desirable to operate the vertical adjustment of the wheel from either end of the machine base. As illustrated in the drawings, the shaft 3| is preferably supported in a quill or sleeve 35 which is supported in a cylindrical aperture 36 in the base Ill. The casing surrounding the cylindrical bore 36 is slotted at its lower edge and arranged to bind or clamp the quill 35 in place by means of a clamping screw 31. A similar bore 38 is provided at the opposite end of the machine base II]. This bore is also provided within a slotted casing 39 which may be clamped by means of a binding screw 40. The wheel adjusting unit supported by the quill 35 may be readily removed by unclamping the screw 31 and withdrawing the entire unit including the bevel gear 32 out of the bore 86 and placing the quill 35 within the bore 38 so that the machine may be set up so that the wheels may be adjusted vertically from either end of the machine base, depending upon the particular set-up of the machine.

Transversely movable carriage The base I8 also supports a transversely moverable hand wheel 89 which is mounted on the piston I5 is slidably mounted within the cylinder outer end of a feed screw 58. The feed screw 58 is rotatably supported in bearings iii and 52 which depend from the under side of the carriage 45. The screw 58 engages a nut 53 which is fixed to the base I8 so that any rotary motion of the screw 58 will cause a transverse movement of the slide 85 relative to the base i8. To facilitate adjustment of the transverse slide so that it may be. adjusted from either the front or rear of the machine, a manually operable hand wheel 54 is provided on the rear. end of the feed screw 58. I

The transversely movable carriage is provided with a fiat way 58 and a V-way 59 which serve to support a longitudinally movable work supporting table 68. The table 88 is provided with a pair of mating ways comprising a flat way 8? and a V-way'82.

The table 88 supports a swivel table 53 which in turn serves as a support for rotatable work supporting members including a headstock 84 having a headstock center 85 and a rootstock 68 having a footstock center 61 which serve to rotatably support a fluted cutter or other work piece or tool to be ground in operative relation with the grinding wheels i6 and I1.

The longitudinally movable work table 58 may be traversed or reciprocated longitudinally relative to the carriage 45 and the base I8 either manually or by a power operated mechanism, as'will be hereinafter described. The power op-' erated mechanism preferably comprises a fluid pressure system comprising a cylinder I8 which is provided with supporting brackets II and 12 which are supported on the lugs I8 and 14 which are formed integral with the carriage 45. A

18 and is connected with-a double end piston rod 18 which extends through cylinder heads I1 and I8, respectively. The piston rod I8 is provided at its opposite ends with nuts I8 and 88, respectively, which are in turn connected with depending brackets 8I and 82 depending from the under side of the table 88. t

The brackets 8I and 821 are preferably detachably connected to the piston rod I5 by means of vertical slides 88 and 84 which in a downward position engage the rear surface of the nuts I9 and 88 so that when fluid under pressure is admitted to either a cylinder chamber 85 or a cylinder chamber 88, to move the piston 15 relative to the cylinder I8, a corresponding movement will aromas" together with the brackets 0| and 02 will slide over the nuts 19 and 88 and permit table move-.

ment independent of the fluid pressure piston.

A fluid pressure system is provided to convey fluid under pressure to the cylinder I8 to cause a longitudinal movement of the piston I5 so as to traverse or reciprocate the work supporting on integral valve pistons 91, 98, 99, I88 and I8I.

Fluid under pressure from a pipe or passage 94 passes through a pipe or passage I82 into a valve chamber I83 between the valve pistons 98 and 99 and in the position shown in Fig. 4 passes out through a pipe or passage I84 into a passage I85 within the cylinder casing 18 and into ,the

cylinder chamber 85 to cause the piston I5 to move toward the right, as viewed in Fig. 4.

During the movement of the piston I5 toward the right, as above described, fluid exhausts from cylinder chamber 85 through a passage I81 within the cylinder casing I8 and through a pipe or passage,i88 into a valve chamber 889 between the valve pistons 99 and I88 and out through a pipe or passage I 58.

In order to control the speed of movement of the-table 68, a control valve H2 is provided in the system and is preferably located in the exhaust side of the system so as to control the exhaust of fluid from the cylinder chamber 85 or 85. The control valve H2 is preferably of a piston type and comprises a valve stem I it having formed integrally thereon valve pistons II4, H5 and H5. The pipe or passage. H8 conveys fluid into a V-shaped chamber III which is cut in the periphery of the valve piston H5, which passes out through a port H8 and through a passage H9 and is returned to the reservoir 98. As indicated in Fig. 4, fluid returns through a pipe I28 to the reservoir 98. In actual construction, however, as shown in Fig. 6 of the drawings, the passage H9 in the valve II2- exhausts fluid from the system into a chamber I2I formed in' the transversely movable carriage 45 and passes from the chamber I2I through a short tube I22 (Fig. 5) into the base I8, the lower portion of which is formed as a reservoir 98. The tube I22 passes through an elongated slot I28 in the base I8. The slot! is of sufllcient length to allow the desired transverse movementof the carriage".

Inidrderf'to control the speed of movement of the table 88, the V-shaped chamber within the valve piston H5 may be rotated to vary the aperture of the port H8. To facilitate a rotary adjustment of the valve member, and particularly the V-port I", a control knob I25 is fixedly mounted on the outer end of the valve stem H8.

It is desirable to be able to quickly slow down the table 88 to a predetermined slow uniform speed for truing and then to rapidly return the table to the desired grinding speed. This is preferably accomplished by providing markings or graduations on the dial face of the knob I25 which may be turned to coincide with an index marker I28 which is carried by a bushing I21. In order to hold the valve in adjusted position, the valve stem II8-is provided with a serrated portion 124 which is engaged by a spring-pressed pawl I28 supported in the valve casing of the vale- II2. In order to provide a quick adjustment of the speed to produce a slow truing speed,

the dial I25 is provided with a rearwardly projecting lug I29 which is arranged in the path of an adjustable stop screw I30 carried by the bushing I21. The screw [30 is adjusted so as to locate the V-port I H in the valve I I5 in the desired relationship with the port 8 to produce.

the desired slow table speed for truing of the grinding wheels. The knob I25 may then be rotated to open the V-port II1 and allow the table to travel at the desired grinding speed. At any time during operation of the machine, the knob I25 may be quickly and readily turned until the lug I29 engages the end of the stop screw I66 to produce a slow uniform truing speed of the table. The screw I60 is preferably provided with a lock nut I3I which serves to lock the screw in its predetermined adjusted position.

When it is desired to stop the fluid pressure traverse of the Work table 60, the valve stem H6 may be moved toward the left, as viewed in Fig. 4, which serves to move the V-port H1 in the piston H5 into the position IITia, thereby closing the passage or pipe II and cutting 0d the exhaust of fluid from the cylinder chamber 66. At the same time, the movement of the valve piston serves to move a valve chamber I35 between the -valve pistons M and H6 toward the left, as viewed in Fig. 4,so that fluid exhausting from the cylinder chamber 66 may pass through the valve chamber I09 in the reversing valve 95 and through a pipe or passage I36, through the valve chamber I35, and through a pipe or passage I31, which is connected with the valve chamber I 03. The valve chamber I03 is connected by the pipe I06 and the passage I05 with the cylinder chamber 85, thereby allowing fluid within the system to readily by-pass from the cylinder chamber 86 to the other cylinder chamber 85 when the control valve is in a stopped position. This by-pass from one cylinder chamber to the other permits the table to be readily traversed manually without the necessity of overcoming pressure of fluid within the fiuid pressure system.

In order to readily control the in-and-out movement of the valve, a control lever I60 is pivotally mounted on a stud III supported on a bracket I 62. The lever I60 is provided with an enlarged portion I43 having an aperture I06 which surrounds the bushing I21. The lever I 60 is provided with a pair of diametrically opposed screws I65 and I 16. the inner ends of which ride in slots I61 and I98 cut in the periphery of the bushing I21 so that when the lever I 60 is moved from the table operating position, as shown in full lines in Fig. 6, into a broken line position Mild to close the valve, it serves to move the valve stem II3 toward the right, as viewed in Fig. 6, to close the V-port I11 and open the bypass between the opposite ends of the cylinder. The bushing I21 is provided with a depending pin I69 which engages a slot I50 in the lever I60 and serves to hold the bushing I21 against rotation. I

To facilitate reversing the direction of movement of the table either automatically or manually, a reversing lever I55 is provided. This lever is provided with a slot I56 at its lower end and is arranged to fit upon a transversely extending rock shaft I51 and may be clamped in adjusted position thereon by means of a clamping screw I58. The shaft I51 is supported in bearings I59 in the transversely movable carriage 45. A de- -held in position thereon by a nut I6I.

pending arm I60 is keyed to the shaft I51 and The lever I60 has a projecting boss I62 which supports a lever I69, the upper end of which is provided with a pin I64. The pin I64 engages a groove I65 in a spool shaped member I66 mounted on the endof the reversing valve stem 96 so that when the lever I63 is rocked on the boss I62, it will transmit an endwise movement to the valve stem 96 to reverse the valve and thereby change the direction of movement of the fluid under pressure within the system. The lower end of' the lever I60 is provided with a pair of outwardly extending bosses I61 and I68, each of which sup ports a spring-pressed plunger I69 and I16, respectively. The plungers I69 and I engage opposite sides of a circular end portion III of the lever I63 and serve as a load-and-fire mechanism to aid in throwing the reversing valve into a central position. Each of the plungers is backed by a spring I12 and I13, respectively, the tension of which may be adjusted by means of adjusting screws I16 and I15.

In order to automatically reverse the movement of the table 60, a pair of adjustable table dogs I16 and I11 are adjustably supported in a T slot in the front edge of the table 60. When the table is reciprccated longitudinally, the movement continues until the dog I16 contacts the lever I55. The table 60 is moving toward the right, as viewed in Fig. 5. This movement continues until the table dog I16 strikes a projecting arm I19 of the reversing lever I55 and rocks I13 until there is sufficient energy in the springto shift the lever I63 so as to move the valve stem 96 toward the right, as viewed in Figs. 4 and 5.

The movement of the valve stem 96 toward the right continues under the influence of the lever I55 until the valve piston 98 moves toward the right a suflicient distance to allow fluid under pressure to pass through a port I65 and into a valve chamber I 66 between the valve pistons 91 and 98. Due to the fact that the efiective cross sectional area of the piston 98 is greater than the eifective cross sectional area of the piston 91, the fluid under pressure entering the chamber I86 serves to complete the movement of the valve stem 96 toward the right, as viewed in Fig. 4,

shifting the valve into its extreme right-hand po-' sition so. that fluid under pressure passing through the pipe or passage 66 passes through a pipe or passage I81 into the valve chamber I09 between the valve pistons 99 and I00 and out through thepipe or passage I08 into cylinder chamber 66 to cause the piston and the table 60 to move towardthe left, as viewed in Fig. 4. When the table reaches .the end of its stroke toward the Ieft, the reversal is automatically made in a manner similar to that described above. The dog I11 serves to rock the reverse lever I55 to move the valve stem 96 until the valve piston I00 uncovers a valve port I88 to admit fluid under pressure into a valve chamber I89 between valve pistons I00 If it is desired'to traverse the table beyond the normal reciprocatory stroke thereof, it is desirable to provide means to render either the reverse lever or the dogs inefl'ective. In the preferred construction, as illustrated in the drawings, the reverse lever I55 is made in two parts. The upper portion I55 slides on a cylindrical lower portion I90 and is normally held in an upward position by means of a spring I9I. If it is desired to pass beyond either the table dog I16 or I11, the knob I92 of the reversing lever I55 may be pushed downwardly against the tension of the spring I9I to lower the projecting arm I19 below the path of the dogs H6 or I11. A pin I93 in the lever I55 engages an elongated slot I94 in the lower portion I90 and serves to maintain the arm 119 in the proper position. The elongated 'slot I94 is required when the knob I92 of the reverse lever I55 is pushed downwardly so that the arm I19 will be below the dogs I16 and I11.

The reversing lever I55 may be, either actuated automatically by means of the table'dogs or manually by means of the knob I92. In certain types of tool grinding, it is desirable for the operator to stand at the rear of the machine in order to control the movement of the tool relative to the grinding wheel and to observe the grinding operation as it proceeds. In this case, it is desirable to provide an auxiliary reversing lever I95 which is clamped by means of a screw I96 on the rear end of the shaft I51 so that the reversing valve may be manually operated from the rear of the machine.

,A manually operable traversing mechanism is provided for manually reciprocating or traversing 'the table 60. This mechanism, as illustrated, is

preferably of a two feed type, such as that'disclosed in the prior patent to Norton and Turner No. 1,299,765 dated April 8, 1919. Thetable 60 is provided with a depending rack bar 200 which meshes with a gear 20I which is slidably keyed to a rotatable shaft 202. The shaft 202 is suported in bearings 203 and 204 in the carriage 05. A large gear 205 is keyed to the outer end of the shaft 202. A manually operable hand traverse wheel 206 is rotatably mounted on an outwardly extending shaft 201. The hand wheel 206 carries a rotatable shaft 208 having formed integrally thereon a gear 209 which meshes with the internal gear 2I0, which is mounted on the hub of a gear 2i I which is rotatably mounted on the shaft 201. Gear 2 meshes with the gear ,205. The shaft 298 rotatabiy supports a gear 2I2 which in turn meshes with a non-rotatable internal gear 219 which is fixed relative to the carriage 45. In the position of the parts illustrated, when the hand wheel 206 is rotated to traverse the table, this rotary motion is transmitted through the teeth of the gear 209 to rotate the gear M at the same speed at which the hand wheel is rotated to transmit .a rotary motion through the gears ZII and 205 to rotate the shaft 202 and the gear 20I to cause a longitudinal traversing or reciprocatory motion to the table 60.

The outer face of the gear H2 is provided with clutch teeth 2 which are arranged to be engaged by clutch teeth M5 on a movable clutch member NS. The clutch member 2I6 is slidably ,keyed to the shaft 208 and is arranged to be moved into or out of operative engagement with the clutch teeth 2 by means of a control knob 2". A pair of diametrically opposed springpressed plungers carried by the member 2I9 engage grooves in the outer periphery of the' s eve formed integral with the clutch member 2| and serve to hold the clutch member 2I6 either out of operative engagement, as shown in Fig. 8, or into operative engagement when the knob 2I1 is pushed toward the right, as viewed in Fig. 8.

The pressure of the pair of spring-pressed plungers carried by the member 2I8 may be adjusted by the pair of screws 2I9 and check nuts. If a slow hand traversing movement of the table is desired, the knob 2" is pushed toward the right, as viewed in Fig. 8, so that the teeth 2I 5 of the clutch member 2I6 are thrown into engagement with the clutch teeth 2 on the gear 2I2. In this position of the parts, movement of the hand wheel 209 revolves the gears 209 and 2I2 about the axis of the shaft 208, but the pinion 2I2 meshing with a fixed internal gear 2I3 is thereby forced to rotate, turning the gear 209 with it, which in turn rotates the internal gear 2) and causes a differential movement between the parts,

this movement being transmitted to the gears 2| I and 205 to rotate the shaft 202 at a slow feed,

which motion is transmitted to gear 20I to the rack 200. By this mechanism, the table 60 is moved slowly and thereby is obtained a fine position or is produced manually a sufliciently uniform rate of motion for such accuracy of work as is required in truing a grinding wheel. Full details of this mechanism have not been illustrated in the present case, since this feature in itself is not considered part of the present invention. For complete details of the construction of this hand traverse mechanism, reference may be had to the above-mentioned Patent No.

It is desirable to provide a suitable interconnection between the hydraulically operated table reciprocating'mechanism and the manually operable traversemechanism so that when the table 80 is reciprocated by means of the fluid pressure piston and cylinder, the manually operable traverse mechanism will be rendered inoperative so that the hand wheel remains stationary during the power reciprocation of the table 60. This is preferably accomplished by an electrically operated mechanism.- The gear 20I is provided with an extending hub 225 which is provided with a groove 229. The groove 226 is engaged by a projection 221 on a rock arm 228 pivotally mounted on a stud 229. In the full line position of the parts, as illustrated in Fig. 4, the table is under fluid pressure control and the rock am 229 is swung to the dot and dash position so as to slide the gear 20I out of mesh with the rack 200 against the tension of a spring 230. The gear 20I is thrown into the position illustrated in Figs. 4 and 8 by an electrically operated mechanism in,- cluding a solenoid 23L the core of which is connected by a link 232 with the rock arm 228. A limit switch 233 is in a closed position, as indicated in Fig. 4, and serves to energize the solenoid 23! so as to throw the gear 20I out of mesh with the rack bar 200. When it is desired to stop the fluid pressure movement of the table 60, the control lever I00 is moved into a broken line position 0a, as indicated in Fig. 6, which serves to move the valve stem H3 toward the right, as viewed in Fig. 6, so as to move the v-chamber II'II so as to close the pipe or passage H0 and thereby stop the fluid pressure movement of the table 60. This movement also serves to move the fluid pressure chamber I located between the valve pistons H5 and II6 into alignment with the pipesor passages I35 and I31 to allow a by-passing of fluid between the cylinder chambers 85 and 86 on opposite sides of the piston 15. During this movement of the control valve II2, a projecting pin 22! on' the valve stem 3 engages a roller 235 which is mounted on a rock arm 236 ofthelimit switch 233. The pin 234 serves to rock the arm and the roller into the dotted line position 235a which serves'to open the circuit of the electrical contact portion of the rock arm 236 against the tension of the spring 231, thereby deenergizing the solenoid 23I and allowing the released tension of the spring 230 to throw the gear 20I into mesh with the rack bar 200 so that the table may be traversed manually by rotating the manually operable traverse wheel 20I. Similarly, when it is desired to start the table movement under the influence of fluid under pressure, the control valve lever is moved from the position I40a into the full line position I40, as indicatedin Fig. 6, which serves to move the valve stem II3 toward the right, as viewed in Fig. 4. This movement cuts off the by-pass of fluid between the pipes I36 and I31 and moves the Vchamber II'I into alignment with the pipe I I to allow fluid pressure to exhaust from the system. At the same time, the valve stem 3 is moved toward the right, Fig. 4. The pin 234 on the valve stem I I3 moves into the position as illustrated in Figs. 4 and 6 out of contact with the roller 235, allowing the rock arm 236 to assume the full line position of the parts, as illustrated in Fig. 4, thereby closing the circuit to energize the solenoid 23I. The energizing of the solenoid 23I serves to move the link 232 and rock the arm 22:; in a clockwise direction (Fig. 4) to move the gear 20I out of mesh with the rack bar 200 and thereby to render the manual traverse mechanism inoperative during thetable traverse movement under fluid pressure.

In the grinding of straight fluted and spiral tools, such as reamers or milling cutters, it is necessary for the cutter to be mounted on centers 65 and El and the cutting edge to be ground located by means of a tooth rest (not shown). The tooth rest serves to maintain either the straight cutting edge or the spiral edge in proper operating position relative to the grinding wheels I6 or I I. It is necessary in such an operation to cause one complete reciprocation of the table, that is for the table to grind across the cutting edge once in each direction and to then stop so as to permit indexing of the cutter to bring the next tooth into operative relation with the wheel. In such an operation, the operators attention must be directed to maintaining the tool in operative contact with the tooth rest and it is, therefore, desirable to provide a suitable means for causing one complete reciprocation of the table and then stopping the same automatically without attention on the part of the operator. This is preferably accomplished by providing a third adjustable table dog 240 which is reversible and interchangeable so that it may be located either in the full line position, Fig. 5, or in the broken line position 240a at the other end of the table. The dog 240 is arranged to engage a fixed stop 24I or 242 at the end of the table stroke. The dog 240, when used, is preferably located on the other side of the dog I16 in a definite relationship with the reversing dogs I16 or I", depending upon which of the fixed stops I and 242 is used, so that the reversing dog I16 will not contact the projection I19 of the reversing lever N35. The dog ill will contact the projection I19 and reverse the table 60 and when the dog 240 contacts the stop I, the stroke is complete. The dog 24 engages the fixed stop 2 or 242 so as to stop the longitudinal movement of the table 60 and to hold the table stationary against the fluid pressure mechanism, tending to traverse the table. In case the pressure builds up within the system beyond a desired point, a release valve 243 in the pipe line 93 opens and allows the excess fluid under pressure to exhaust through a pipe 244 into the reservoir 90. With this arrangement of the parts, the machine may be set up to grind a fluted cutter, starting either at the headstock or footstock end of the machine, and the lever I55 is thrown manually to start the table moving in one direction while the operator holds the fluted cutter in operative relation with the tooth rest. The table continues its stroke in one direction and the dog I16 or I'll engaging the projection I19 of the reverse lever I55 causes a reverse movement of the table 60, passing the cutting edge of the cutter again across the face of the wheel until the stop dog 240 or 240a. engages the fixed stop 24I or 242 so as to stop the table movement after one complete reciprocation so as to permit indexing of the cutter to move the next edge to be ground into operative relationwith the wheel and tool threads.

It will thus be seen that there has been provided by this invention apparatus in which-the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodient above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to ,move the grinding wheel, and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure system including a piston and cylinder operatively connected to reciprocate the table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve which serves in one position to control the speed of movement of the table and in a second position to permit a by-passing of fluid from one end of the cylinder to the other, and means actuated by .the movement of the control valve to render the manual traverse mechanism inoperative.

2. A grinding machine comprising a rotatable grinding wheel, a rotatable work support,a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure system including a piston and cylinder to reciprocate the table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve which serves in one position to control the speed of movement of the table and in a second position to permit a by-passing of fluid from one end of the cylinder to the other, and means actuated in timed relation with the movement of said control valve to render the manual traversing mechanism operative.

3. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movabletable for said support, means to move the grinding wheel and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure system including a piston and cylinder to reciprocate the table longitudinally, means inof movement of the table, a control valve which serves in one position to control the speed of movement of the table and in a second position to permit a by-passing of fluid from one end of the cylinder to the other, and electrically operated means actuated by movement of said control valve to render the manual traversing mechanism inoperative when the control valve is moved to reciprocate the table by fluid pressure.

4. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure system including a piston and cylinder to reciprocate said table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve in said system which is arranged to stop and start the table reciprocation and to control the speed of movement of the table, electrically operated means including a limit switch which is actuated by movement of said control valve, and means including a solenoid controlled by said switch and arranged to render the manual traverse mechanism inoperative during the fluid pressure reciprocation of the table.

5. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure system including a piston and cylinder toreciprocate said table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve in said system which is arranged to stop and start the table reciprocation and to control the speed of movement of the table, electrically operated means including a limit switch which is closed by movement of said valve into a table recipro Qating position, a solenoid controlled by said switch, and means actuated by said solenoid to, render the manual traverse mechanism inoperative during the fluid pressure reciprocation of the table.

6. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manual means including a rack and gear to traverse said table longitudinally, a fluid pressure system including a piston and cylinder to reciprocate said table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve in said system which is arranged to stop and start the table reciprocation and to control the speed of movement of the table, means to hold said gear in engagement with said rack, electrically operated means including a solenoid to disengage the gear from the rack, and means including an electric switch which is actuated by movement of said control valve which serves to render the manual traverse mechanism inoperative during the fluid pressure reciprocation of the table.

7. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manually operable traverse mechanism including a manually operable hand wheel, a rack and gear interposed between the hand wheel and table, a fluid pres sure system including a piston and cylinder to reciprocate said table longitudinally, means including a reversing valve to change the direction of movement of the table, a control valve in said system which is arranged to stop. and start the table reciprocation and to control the speed of movement of the table, yieldable means to maintain said gear in mesh with said rack, electrically operated means including a solenoid to disengage said gear from the rack, and electrically operated means including a limit switch which is actuated by and in timed relation with said control valve to disengage said gear from the rack and render said manual traverse mechanism inoperative during the fluid pressure reciprocation .of the table.

8. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, manual means to traverse said table longitudinally, a fluid pressure mechanism including a piston and cylinder which are operatively connected to reciprocate said table, a reversing valve therefor, a control valve which is arranged to stop and start said table and to throttle the exhaust of fluid from said cylinder to control the table speed, a

. manually operable lever on the front of said matransversely relative to eachother, a fluid pressure system including a piston and cylinder to reciprocate said table, a reversing valve therefor, a control valve to stop and start said table and to throttle the exhaust of fluid from said cylinder to control the table speed, a manually operable lever to actuate said reverse valve, ad-' justable dogs on said table to actuate said lever to automatically reciprocate said table, and means including an adjustable dog on said table and a fixed stop on said base to stop the table movement after one complete reciprocation thereof.

10. A grinding machine comprising a rotatable grinding wheel, a rotatable work support, a longitudinally movable table for said support, means to move the grinding wheel and work support transversely relative to each other, a fluid pressure system including a piston and cylinder to reciprocate said table, a reversing valve therefor, a control valve to stop and start said table and to throttle the exhaust of fluid from said cylinder to control the table speed, a manually operable lever to actuate said reverse valve, ad- :Iustable dogs on said table to actuate said lever to automatically reciprocate said table, and means including an adjustable dog on the table and a fixed stop cooperating therewith to stop the table at either end of its stroke after one complete reciprocation.

CHARLES H. AMIDON. 

